Proteus spp.

:Prepared byHoven JalalElaf Abdulhakem

Objectves:Morphology of proteus spp.

Microscopical morphologyColony morphology

Diagnostic methods of proteus spp.Gram stainCulture &isolation on blood agar,macconkey agarOxidase testImvic testTSI testMotility testSwarming phenomenonApi &vitek system

General charachteristic:Gram negative rods, facultative anaerobics .

Motile they have peritrichous flagella

Non capsulated

Non spore forming

Proteus sp. are most commonly found in the human intestinal

tract as part of normal human intestinal flora.

Non-lactose fermenting

The main species of medical importance are:P. mirabilis

P. vulgaris

Proteus spp. are opportunist pathogens and may

cause many types of infection .

Morphology of proteus spp

Microscopical morphologyGram negative bacilli, motile has flagella

Colony morphology:

Large ,circular,gray ,smooth colonies

Diagnosis method of proteus spp.

Specimens :

Urine, pus and ear

Gram stain:

Rod shaped gram negative

Culture:

Blood agar: Swarming effect over blood agar plate as a consequence of the organisms active

motility.

Macconkey agar: Cultures give out an odour described as fishy, Non- lactose fermenting colonies.

Oxidase test: The oxidase test is used to determine if a

bacterium produces certain cytochrome c oxidases. The reagent turns dark blue when oxidized (oxidase positive). The reagent is colorless when reduced (oxidase-negative)

Proteus spp. Oxidase negative

IMViC test1-indole test:

is used to determine the ability of bacteria to convert tryptophan into indole.

P. mirabilis can be differentiated from p.vulgaris by indole test.

P. mirabilis → negative P. vulgaris → positive

Methyl red test: .The methyl red test is used to identify bacteria

to produce pyruvic acid from glucose metabolism.

Proteus vulgaris:Methyl red: posativeProteus mirabils:

Methyl red: posative

Voges–Proskauer: •is a test used to detect acetoin in

a bacterial broth culture. A red-brown color indicates a positive result, while a yellow-

brown color indicates a negative result .p.Vulgaris : Negative

p.mirabilis:negative

Citrate test:Ability of an organism to use citrate as the sole

source of carbon and energy.

p.Vulgaris: Negative

p.mirabilis: posative

TSI testTriple Sugar Iron test

This test is used to determine the ability of bacteria to ferment sugars and to produce hydrogen sulfide (H2S) or other gases

Proteus spp .(red/red with H2S production)

(black)

Motility test

 used to determine whether an organism is equipped with flagella and thus capable of swimming away from a stab mark.

•Left tube shows positive motility test for Proteus spp.

•Right tube negative for S.aureus

Swarming phenomenon swarming is described as the formation of

concentric zones of bacterial growth, able to cover the whole surface of solid culture medium.

P.mirabilis & P.vulgaris are known for their swarming ability over(sheep blood agar)

APIBy inoculating microorganism to a strip that has 20 tests on it. during inoculation metabolic cause color change, to complete the identification of the strains either identified to the genus only or that have multiple genera consist of profile number

Vitek systemIt is a new automatic system for identification and susceptibility testing for most of clinically important bacteria.It compromises:

-A filtter/sealer:enable -inoculation of the card

within few minute.-An inoculator /leader

-A computer and printer